Kevin will take 4 math tests this term. All of the tests are worth the same number of points. After taking the first 3 tests, his mean test score is 88 points. How many points does he need on his last test to raise his mean test score to 90 points?

Kevin needs 96 points on his last test to raise his mean test score to 90 points.

Step-by-step explanation:

we know that

The mean score is the total of all scores divided by the total number of tests.

Let

x_1 ----> the score in the first math test

x_2 ----> the score in the second math test

x_3 ----> the score in the third math test

x_4 ----> the score in the fourth math test

we have

After taking the first 3 tests, his mean test score is 88 points

so

----> equation A

How many points does he need on his last test to raise his mean test score to 90 points?

so

----> equation B

substitute equation A in equation B

solve for x_4

Therefore

Kevin needs 96 points on his last test to raise his mean test score to 90 points.

the circle graph is not a function.

step-by-step explanation:

the graph of the circle is not a function.

because for a graph to be a function, each value of x must give one value of y

in the circle, the values of x for -2< x< 2 each give 2 values of y.

hence this is not a function.

my answer is$ 12

step-by-step explanation:

because 15 -2=12